Bichel [Bichel, Nature 231: 449-450 (1971)] reported that removing most of the tumor from mice bearing ascites tumors at a plateau of tumor growth was followed by a marked increase in the growth of the remaining tumor cells. Injection of cell-free ascites, obtained from mice bearing fully developed ascites tumors, into mice with growing ascites tumors resulted in a pronounced inhibition of ascites growth. Bichel, supra, also observed that two surgically joined mice (parabiotic), one mouse with an advanced tumor and the other with an early tumor, resulted in a pronounced inhibition of growth of the early tumor. Based upon these observations, [Bichel, Europ. J. Cancer 6: 291-296 (1970) and Bichel, supra] the existence of a diffusible inhibitory principle which circulated through the peritoneum of the parabiotic mice and was present in the cell-free ascites fluid produced by the fully developed ascites tumors was postulated. The nature of this inhibiting principle was not characterized, but it was speculated that the rate of growth of the ascites tumors was dependent upon the amount of tumor tissue and was determined by the amount of inhibitory principle produced.
Substances having tumor growth inhibitory activity have been described. [Holley, et al., Proc. Natl. Acad. Sci. USA 77:5989 (1980) and Holley, et al., Cell Biol. Int. Reports 7: 525-526 (1983)]. These publications report the isolation from African green monkey BSC-1 cells of a growth inhibitory substance which inhibited the growth of BSC-1 cells, human mammary tumor cells and normal human mammary cells. This substance has recently [Tucker, et al., Science 226: 705-707 (1984): Roberts, et al. Proc. Natl. Acad. Sci. 82 (Jan): 119-123 (1985)] been shown to be identical, or highly related, to a 25,000 dalton two chain human platelet-derived polypeptide designated xcex2-TGF (Assoian, et al., J. Biol. Chem. 258: 7155-7160 (1983)]. Independently, McMahon, et al. [Proc. Natl. Acad. Sci. USA 79, 456-460 (1982)] have purified from rat liver a 26,000 dalton substance which inhibits the proliferation of nonmalignant rat liver cells, but does not inhibit the proliferation of malignant rat liver cells. Other growth inhibitory substances have been identified in cultured chick spinal cord cells [Kagen, et al., Experimental Neurology 58: 347-360 (1970); Harrington, et al., Proc. Natl. Acad. Sci. USA 77: 423-427 (1980) and Steck, et al. J. Cell Biol. 83: 562-575 (1979)].
Iwata, et al., [J. Cellular Biochem. Suppl. 5: 401 (1982)] previously described a microtiter plate system for assaying growth stimulation and growth inhibition activity. Todaro, et al. [Todaro, et al., in Tumor Cell Heterogeneity; Origins and Implications, Bristol-Myers Cancer Symposia, Volume 4, Owens, A. H., Coffey, D. S., and Baylin, S. B., Eds. (Academic Press, 1982), pp. 205-224)] and Iwata, et al. [Fed. Proc. Fed. AM. Soc. Exp. Biol. 42: 1833 (1983)] previously reported the isolation of tumor inhibitory activity from tissue culture fluids of human tumor cells propagated in culture. The observations described in these reports were preliminary and little detail was provided.
On Apr. 20, 1984, a patent application was filed with the United States Patent and Trademark Office under U.S. Ser. No. 602,520, entitled xe2x80x9cSubstantially Purified Tumor Growth Inhibitory Factor (TIF)xe2x80x9d on which one of us, Kenneth K. Iwata, is named as coinventor. This application concerns the preliminary identification of a not well-defined substance or substances present in, and derived from, human tumor cells propagated in culture. This substance or substances resembles the tumor inhibitory activity previously reported. [Todaro, et al., in Tumor Cell Heterogeneity; Origins and Implications, Bristol-Myers Cancer Symposia, Volume 4, Owens A. H., Coffey, D. S., and Baylin, S. B., Eds. (Academic Press, 1982), pp. 205-224); Iwata, et al., Fed. Proc. Fed. Am. Soc. Exp. Biol. 42: 1833 (1983].
Todaro [Todaro, G. J. in Epigenetic Regulation of Cancer, Terry Fox Cancer Research Conference (University of British Columbia; Vancouver, B.C., Canada) Abs. 13 (1984)] recently reported two factors with tumor cell growth inhibitory properties which were reportedly sequenced and shown to consist of 70 and 90 amino acid residues, respectively. Neither the source, i.e. cell, tissue type of species, or the method of purification of the factors were disclosed.
This invention is directed to a method of treating a burn or healing a wound in a mammal by administering a chromatographically recovered polypeptide having the N-terminal amino acid sequence Ala-Leu-Asp-Thr-Asn-Tyr-Cys-Phe-Arg-Asn-Leu-Glu-Glu-Asn-Cys-Cys-Val. This polypeptide is known as TGI, TGI-1 and TGI-2. It is also referred to as TGF-xcex23. The invention is also directed to compositions which comprise the chromatographically recovered polypeptide. The invention also provides pharmaceutical compositions to inhibit the growth of epithelial cells or heal a wound or treat a burn consisting of the chromatographically recovered polypeptide.